Information processing apparatus and battery degradation detection method

Abstract

According to one embodiment, an information processing apparatus is configured to be powered by a battery. The apparatus includes a charging circuit, a charging current measuring module, a charging time measuring module, and a calculation module. The charging circuit charges the battery by using power from an external power supply. The charging current measuring module measures a charging current supplied to the battery from the charging circuit. The charging time measuring module measures a time during which the battery is charged by the charging current. The calculation module calculates a charging capacity from the measured charging current and the measured charging time, and compares an accumulated charging capacity, which is obtained by cumulatively adding the calculated charging capacity to a previously calculated charging capacity, with a reference value, in order to detect degradation of the battery.

What is claimed is: 
     
       1. An information processing apparatus configured to be powered by a battery, comprising:
 a charging circuit configured to charge the battery with power from an external power supply; 
 a charging current measuring module configured to measure a charging current from the charging circuit to the battery; 
 a charging time measuring module configured to measure a time during which the battery is charged by the charging current; and 
 a calculation module configured to calculate a charging capacity from the measured charging current and the measured charging time, to calculate an accumulated capacity reference value indicative of a total chargeable capacity of the battery, which is chargeable until a ratio of a chargeable capacity of the battery to a rating capacity of the battery decreases to a predetermined ratio, based on characteristic information of the battery, and to compare an accumulated charging capacity, which is obtained by cumulatively adding the calculated charging capacity to a previously calculated charging capacity, with the accumulated capacity reference value, in order to detect degradation of the battery, wherein the characteristic information is indicative of the rating capacity of the battery and a chargeable capacity decrease rate of the battery, and wherein the chargeable capacity decrease rate is indicative of a ratio of the chargeable capacity which is decreased when full-charging of the battery is executed a predetermined number of times. 
 
     
     
       2. The information processing apparatus of  claim 1 , wherein the characteristic information of the battery is stored in a nonvolatile memory in the battery. 
     
     
       3. The information processing apparatus of  claim 1 , wherein the calculation module is configured to store the accumulated charging capacity in a nonvolatile memory in the battery. 
     
     
       4. The information processing apparatus of  claim 1 , further comprising an indicator configured to indicate degradation of the battery if the accumulated charging capacity exceeds the accumulated capacity reference value. 
     
     
       5. A method of detecting degradation of a battery configured to be attached to an information processing apparatus, comprising:
 measuring a charging current from a charging circuit to the battery, the charging circuit being configured to charge the battery by using power from an external power supply; 
 measuring a time during which the battery is charged by the charging current; 
 calculating a charging capacity from the measured charging current and the measured charging time; 
 calculating an accumulated capacity reference value indicative of a total chargeable capacity of the battery, which is chargeable until a ratio of a chargeable capacity of the battery to a rating capacity of the battery decreases to a predetermined ratio, based on characteristic information of the battery, wherein the characteristic information is indicative of the rating capacity of the battery and a chargeable capacity decrease rate of the battery, and wherein the chargeable capacity decrease rate is indicative of a ratio of the chargeable capacity which is decreased when full-charging of the battery is executed a predetermined number of times; and 
 comparing an accumulated charging capacity, which is obtained by cumulatively adding the calculated charging capacity to a previously calculated charging capacity, with the accumulated capacity reference value, in order to detect degradation of the battery. 
 
     
     
       6. The method of  claim 5 , wherein the characteristic information of the battery is stored in a nonvolatile memory in the battery. 
     
     
       7. The method of  claim 5 , further comprising producing a warning output to indicate degradation of the battery if the accumulated charging capacity exceeds the reference value.